Journal of Engineering

This study explores traditional solutions in sustainable climatic adaptation and their application in contemporary housing, particularly in hot dry climate regions. The research focuses on analyzing traditional urban fabric components and their ability to create comfortable microclimates. By studying the compact forms and design principles of traditional architecture, the study aims to develop criteria for contemporary housing that can address current environmental challenges. The findings highlight the importance of integrating ecological, technological, economical, and social systems to form sustainable urban environments. The research concludes that traditional architectural practices can provide valuable insights for designing sustainable and comfortable housing units in contemporary settings.

تتناول هذه الدراسة تثبيت نظام المعلومات الجغرافية (GIS) في العراق، وتسلط الضوء على أهمية هذا النظام في تحليل ومعالجة البيانات الجغرافية، خاصة في سياق النمو الحضري. تم تطوير نموذج مفهومي يمكنه التعامل مع مجموعة متنوعة من الأشياء والعلاقات المهتم بها للمخططين الحضريين، مما يسهم في تحسين عملية التخطيط الحضري والتصور السريع ثلاثي الأبعاد. تم تطبيق هذا النظام في بغداد كجزء من محاولة لتوفير نظام يلبي احتياجات المستخدمين ويحل مشاكل التخطيط الحضري والمعلومات.

تتناول هذه الدراسة تأثير استخدام انواع مختلفة من البوزولانات المحلية على إنتاج خرسانة عالية الأداء. تم إجراء تجارب تجريبية لتقييم الخصائص الفيزيائية للخرسانة مثل القوة الضغطية والصلابة. تم تحليل النتائج ومقارنتها مع استخدام البوزولانات المعروفة مثل البوزولان الصغير. تم الاستفادة من البوزولانات المحلية لتحسين جودة الخرسانة وتقليل تكلفة المواد. تشير النتائج إلى أن البوزولانات المحلية يمكن أن تكون خيارًا ممتازًا لتحسين الخصائص الفيزيائية للخرسانة وتقليل التكاليف.

This study investigates the behavior of embankments constructed on soft clay soils using finite element analysis. The research employs the CRISP (CRItical State Program) to simulate soil deformations under various conditions. The program utilizes eight-node isoparametric quadrilateral elements and fully coupled (Biot) consolidation analysis for two-dimensional plane strain problems. The predictions of displacements and excess pore water pressures were compared with field measurements. The results indicate that the maximum vertical movement occurs below the centerline of the embankment, with settlement decreasing as the distance from the toe increases. Upward movement of the surface far from the toe was also observed. The maximum horizontal movement occurs near the top boundary, with a higher rate of movement at the top compared to the bottom. This behavior is attributed to the flexibility and free movement condition of the vertical boundary in the top half. The study provides valuable insights into the design and analysis of embankments on soft clay soils.

This study investigates the effect of transverse base restraint on the cracking behavior of massive concrete structures. The research includes both thermal and structural analyses using the finite element method. Thermal analysis was conducted to determine the temperature distribution within the concrete due to cement hydration and ambient conditions. Structural analysis adopted the concept of initial strain problems, with drying shrinkage volume changes calculated using procedures suggested by ACI Committee 209. The Willam-Warnke model with five strength parameters was used to model the concrete material, allowing for the inclusion of cracking and crushing behavior. The ANSYS program was employed to perform these analyses on a thick concrete slab with varying aspect ratios. The results indicate an increase in cracking tendency as the aspect ratio increases due to the effect of transverse base restraint. This effect is crucial in the analysis of base-restrained massive concrete structures subjected to temperature and drying shrinkage volume changes.

This paper presents the design of a PID controller for the satellite attitude yaw-axis control system. The PID controller was chosen for its quick transient response and zero steady-state error. A mathematical model of the satellite attitude yaw-axis control system was derived, and MATLAB was used to obtain an optimal controller design. The design aims to achieve the quickest settling time without excessive overshoot and zero steady-state error. The results demonstrate the effectiveness of the PID controller in achieving precise angular positioning of the satellite body using a DC motor.

This paper aims to develop a numerical procedure using the finite element method for analyzing soil consolidation under cyclic trapezoidal loading. The study emphasizes the buildup of pore pressure during loading and unloading cycles. Biot’s consolidation theory is adopted to account for changes in shear stresses and mean normal stresses due to cyclic loading. The results indicate that excess pore water pressure increases with load cycles until steady-state conditions are reached. The study also explores the effects of load application speed on collapse load, with faster loading approaching undrained conditions and slower loading approaching drained conditions. The elastoplastic model predicts significantly higher pore pressures compared to the elastic consolidation analysis due to the inclusion of plastic volume strain.

This paper describes two newly developed detection processes for a modem over the public switched telephone network. The modem is a synchronous serial system using a 16-point QAM signal with a detector. The detector is preceded by an adaptive filter that is adjusted to make the sampled impulse response of the channel and filter minimum phase. The idea of these two new detectors is to transmit known retraining data at specified intervals and use this data to improve the conventional nonlinear equalizer and near maximum likelihood detector. Results of computer simulation tests are presented, comparing tolerance to additive white Gaussian noise with and without retraining. The detectors with retraining achieve better noise performance than conventional detectors. Furthermore, the amount of retraining data is varied to find the best compromise between the efficiency of data transmission and performance improvement.

This study presents the development of an Integrated System (IS) designed to streamline project management processes, particularly for water projects. The system connects three software tools: AutoCAD, Excel, and Ms Project, using Active X data transfer technology. This integration allows for the extraction of graphical information from AutoCAD drawings and its conversion into digital data suitable for processing in project management software. The system was tested on three case studies: the Al-Nahrain University wastewater network, the Islamic University water supply network, and an irrigation and drainage project. The results demonstrate the system's capability to transfer graphical data into digital data and conduct quantity surveys efficiently. The study highlights the potential for this system to reduce the time and effort required for data collection and minimize errors in data transfer, making it a valuable tool for urban planners and project managers.

This study investigates the static behavior of three partially encased composite steel beams with cambering under flexural conditions, focusing on alternative positions for the headed studs. Shear resistance between the cambered I-shaped beam and the concrete was provided by headed studs in two positions: vertically welded on the bottom flange and horizontally welded on the faces of the web. A nonlinear three-dimensional finite element analysis was used to predict the load-deflection and moment-rotation behaviors of the composite encased beams using the finite element computer program (ANSYS V. 10). The results show good agreement with available experimental load-deflection curves. It was found that using a steel section with cambering can increase the ultimate load capacity of the composite encased beam by approximately 15%, and deflections were reduced by 65% to 80% compared to beams without cambering. Parametric studies were conducted to examine the increase in moment-carrying capacity due to the use of encased concrete and the slip along the beam's length. The strain distributions along the steel section and encased concrete depth were also examined, along with the effects of concrete compressive strength on the stiffness of the composite encased beams.

This study investigates the impact of different boundary configurations on the velocity patterns and water quality distribution within Al Huwayza Marsh, the largest marsh in southern Iraq. A two-dimensional depth-averaged hydrodynamic model (RMA2) and a two-dimensional water quality transport model (RMA4) were developed using the Surface Water Modeling System (SMS) software package. The models were applied to three boundary configuration scenarios: the natural extension of the marsh boundary, the existing boundary with a southwest dyke, and a proposed boundary with an additional dyke along the Iraq-Iranian border. The results indicate that flow velocities are highest at the inlets and outlets of the marsh, with significant variations in water flow direction and reduction in discharge due to dyke construction. The mixing process of water from different feeders was also affected, with slight variations in water quality parameters observed in the different scenarios. This study provides valuable insights into the effects of boundary configurations on marsh hydrodynamics and water quality.

This study investigates the static behavior of three partially encased composite steel beams with cambering under flexural conditions, focusing on alternative positions for the headed studs. Shear resistance between the cambered I-shaped beam and the concrete was provided by headed studs in two positions: vertically welded on the bottom flange and horizontally welded on the faces of the web. A nonlinear three-dimensional finite element analysis was used to predict the load-deflection and moment-rotation behaviors of the composite encased beams using the finite element computer program (ANSYS V. 10). The results show good agreement with available experimental load-deflection curves. It was found that using a steel section with cambering can increase the ultimate load capacity of the composite encased beam by approximately 15%, and deflections were reduced by 65% to 80% compared to beams without cambering. Parametric studies were conducted to examine the increase in moment-carrying capacity due to the use of encased concrete and the slip along the beam's length. The strain distributions along the steel section and encased concrete depth were also examined, along with the effects of concrete compressive strength on the stiffness of the composite encased beams.

This paper presents a numerical investigation of the non-cavitating and cavitating performance of a three-blade pump inducer under nominal and off-design operating conditions. Three different simulated hydrofoils—a flat plate, “NACA0004,” and “Clark-Y-6%”—were selected to represent the profile of the inducer blade. A two-dimensional, steady, incompressible, turbulent, and isothermal flow field between the inducer blades was simulated using the finite volume method (FVM). The "Interface Tracking" model was selected to predict the cavity profile of the attached cavitation and the cavitating performance drop. For each blade profile, the influence of solidity in the range of (1.8 to 3.0) and blade angle in the range of (20° to 35°) on the inducer performance was studied. The results indicate that the developed model accurately predicts the general non-cavitating performance for an inducer with a flat plate blade profile. For “NACA0004” or “Clark-Y-6%” hydrofoil blade profiles, a reduction in the operating range of these inducers was observed. Additionally, the developed model predicts the inception of cavitation earlier than the experimental results. The predicted cavitating head drop curve of an inducer with a flat plate blade profile was compared with available experimental results, showing good agreement.

This study presents a numerical analysis of the cooling process of hot water discharge from a steam power plant into a river, focusing on the impact of obstacles in the river on heat dissipation. A mathematical model was developed based on the assumptions of steady-state, two-dimensional, turbulent flow in the horizontal plane. The governing equations include the continuity, momentum,
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turbulence model, and energy equation. Proper initial and boundary conditions were specified, and a numerical solution was obtained using the control volume approach, non-staggered grid technique, and modified SIMPLE algorithm. The results indicate that the presence of an obstacle and its distance from the injection zone significantly affect the temperature distribution and streamline. However, the increase in injection temperature has a minimal effect on these parameters. The developed algorithm accurately calculates the velocity and temperature distributions, providing valuable insights into optimizing the cooling process.

This study numerically investigates the turbulent natural convection heat transfer and fluid flow inside an air-filled inclined square enclosure that is differentially heated. The fully elliptic Navier-Stokes and energy equations are solved using the finite volume method1. The problem is simulated for different angles of inclination (0° ≤ θ ≤ 180°) and Rayleigh numbers (10^8 ≤ Ra ≤ 10^16). The turbulence k-ε model is used to model the effect of turbulence, and the wall function approach is employed to model the regions near the walls of the enclosure1. The results show that the rate of heat transfer increases with the Rayleigh number and decreases with the angle of inclination (0° ≤ θ ≤ 90°). Additionally, the induced vortices are strongly elongated with an increase in the Rayleigh number, and the thickness of the thermal boundary layer decreases with increasing Rayleigh number1. The validation of the present code was done by comparing the computed results with published data, showing good agreement.

This study employs a numerical method to simulate the solidification parameters of an eutectic aluminum-silicon alloy in a chilled metallic mould with copper. The approach is based on solving the heat flow equations of the casting and mould, treating the latent heat as a boundary condition between the liquid and solid phases. The results demonstrate different behaviors of solidification parameters along the casting. Additionally, the simulation approach, combined with microstructure analysis, provides insights into the microstructural features of the alloy system. The findings highlight the potential of numerical simulation to enhance the understanding and optimization of the casting process.

This paper presents a finite element analysis of the vibration characteristics of a rotating pre-twisted cantilever plate. The study investigates the effects of rotation speed, disc radius, aspect ratio, pre-twist angle, and skew angle on the natural frequencies of the plate. A three-dimensional finite element program was developed using three-noded triangular shell elements, which have six degrees of freedom at each node. The initial stress effect (geometric stiffness) and other rotational effects, except the Coriolis acceleration effect, were included in the analysis. The eigenvalues were extracted using the simultaneous iteration technique. The results indicate that the natural frequencies increase with the angular speed and disc radius. The study provides valuable insights into the dynamic behavior of rotating pre-twisted cantilever plates, which are relevant for the design of turbomachinery blades and other rotating structures.

This study investigates the effects of harmonics in the exciting voltage when using a DC/AC inverter on the performance of a single-phase induction motor. The investigation includes both theoretical and experimental parts, with a performance comparison of the motor with the nominal sinusoidal input voltage. The computed performance of the motor depends on the theoretical equivalent circuits, which are modified to account for the existence of harmonics in the inverter output to compute the performance at each harmonic order. The analysis concludes that pulsating torque is inherent in single-phase induction motors, even when supplied from a sinusoidal voltage source. Particular attention is given to the pulsating torque when the motor is supplied from an inverter, and the most important pulsations are identified. The comparisons of simulation and measured results show good correlation, highlighting the cumulative effects of harmonics on the motor performance.

This study investigates the effectiveness of two anionic surfactants, Sodium Dodecyl Benzene Sulfonate (SDBS) and Sodium Lauryl Sulfate (SLS), in reducing drag in a closed loop system. The experimental setup consists of three steel pipes with different diameters (0.75, 1, and 1.5 inches) and a test section length of two meters. The experiments were conducted at three different temperatures (30°C, 40°C, and 50°C) with surfactant concentrations ranging from 50 to 300 weight ppm. Results indicate a direct proportionality between drag reduction percentage and Reynolds number and pipe diameter, while an inverse proportionality is observed with temperature. The highest drag reduction (23.67%) was achieved with 200 ppm SDBS at 30°C. The friction factor values were found to be between the Blasius and Virk asymptotes. This study provides valuable insights into optimizing flow efficiency in pipelines using anionic surfactants.

This study focuses on the preparation of fluorophosphate neodymium laser glass using the discontinuous melting technique. Special melting and casting conditions were employed to prevent devitrification of the glass samples1. The prepared Nd-fluoride glass exhibited a low refractive index, which is crucial for high-power laser applications. Optical properties, including UV-visible and infra-red spectral properties, were investigated1. The UV-visible spectra showed almost total absorbance of light below 400 nm, while the visible range displayed a typical spectrum of Nd3+ ions. X-ray diffraction analysis confirmed the formation of an amorphous phase1. The study provides valuable insights into the characteristics and potential applications of Nd-fluoride laser glass.

This paper explores the use of piezoelectric transducers as both sensors and actuators for controlling the deflection of a simply supported thin beam. The study introduces the concept of a "smart beam," which incorporates a finite number of collocated piezoelectric actuator/sensor pairs. The governing equation for the smart beam is derived using a procedure similar to the Bernoulli-Euler equation, with additional mathematical terms to account for the smart beam characteristics. Engineering control techniques are employed to solve the proposed differential equation, and a block diagram is constructed to model the applied load (static or cyclic) as the input and the beam deflection as the output. An integrated system with a high voltage amplifier and lead controller is designed to achieve efficient deflection reduction. Various cases are studied and simulated, including variations in load nature, frequency, and the number of piezoelectric actuator/sensor pairs, all showing significant deflection reductions. The results demonstrate the potential of piezoelectric transducers in vibration control applications.